Dmytro Dedko (Demetrius Dedko, Ukrainian: Дмитро Дедько) was a Lord of Ruthenia in 1340 (1323) – 1349. Commonly thought to be a Galician boyar, he could be one of sons of Yuri I and Varvara (Barbara). Dmytro is possibly the progenitor of Ostrozky family.Dmytro is mentioned in number of scientific works on history of that period such as "History of Ukraine-Ruthenia" by Mykhailo Hrushevsky, "Die polnische Geschichtschreibung des Mittelalters" by Heinrich Zeissberg and others.